Data communication switches are becoming more and more intelligent. Whereas legacy data communication switches provided indiscriminate first-in, first-out forwarding of packets, more recent data communication switches support differential packet forwarding based on flow characteristics under the Quality of Service (QoS) label. The trend toward QoS started first in cell-switched ATM networks, but has migrated to packet-switched networks and protocols, including bridging (Layer 2, or xe2x80x9cL2xe2x80x9d), routing (Layer 3, or xe2x80x9cL3xe2x80x9d) and transport (Layer 4, or xe2x80x9cL4xe2x80x9d) protocols.
Standardized QoS elements are emerging in packet switched networks. One standard element is a signaling protocol through which a QoS may be provisioned end-to-end for a flow. This signaling protocol is called the Resource Reservation Protocol (RSVP). In conventional RSVP-signaled QoS provisioning, an RSVP-aware source host, called a xe2x80x9csenderxe2x80x9d, desiring to initiate a flow with an RSVP-aware destination host, called a xe2x80x9creceiverxe2x80x9d, transmits downstream an RSVP Path message specifying parameters for a proposed flow. Switches along the flowpath review the RSVP Path message and modify certain message fields as required to indicate limitations and conditions on their ability to deliver QoS services to the flow. The RSVP-aware destination host receives the RSVP Path message and uses the information therein to generate and transmit an RSVP Resv message back upstream requesting the provisioning of a specific QoS for the flow at each switch along the flowpath. Each switch determines whether or not to accept the request based on whether the switch has sufficient available resources to provide the requested QoS and whether the flow is entitled to the requested QoS. If the reservation is accepted, the switches are configured to forward packets within the flow in accordance with the QoS. In this way, an RSVP-signaled QoS for the flow is provisioned end-to-end along the flowpath.
While standard RSVP-signaled QoS, as outlined above, provides a means for end-to-end QoS provisioning within a network, it is only known to be available for flows between hosts that are RSVP-aware. There is a need to extend the benefits of RSVP-signaled QoS to flows involving RSVP-unaware hosts.
The present invention provides RSVP host proxy services for extending RSVP-signaled QoS provisioning to flows involving hosts that are not RSVP-aware.
In accordance with an RSVP sender host proxy service, a switch through which a first host accesses a network acts as an RSVP sender host proxy for the first host. Upon receiving a data packet for a new flow from the first host, and determining that the RSVP sender host proxy service is enabled for the first host, the switch generates and transmits on a flowpath to a second host an RSVP Path message. In accordance with RSVP, the RSVP Path message prompts the second host to generate and return on the flowpath an RSVP Resv message.
In accordance with an RSVP receiver host proxy service, a switch through which a first host accesses a network acts as an RSVP receiver host proxy for the first host. Upon receiving an RSVP Path message generated and transmitted by a second host and determining that the RSVP receiver host proxy service is enabled for the first host, the switch generates and returns on a flowpath to the second host an RSVP Resv message.
A switch serving as an RSVP host proxy for a host may continue to act as an RSVP router for hosts.
These and other aspects of the inventions may be better understood by reference to the following detailed description taken in conjunction with the accompanying drawings briefly described below.